1. Field of the Invention
The present invention relates to an outer rotor motor used for example in an OA appliance such as a printer, a copier, or a DVD drive, an in-vehicle appliance such as a seat cooler or a cooling fan, or a projector.
2. Related Art
One example of an outer rotor-type DC brushless motor will now be described. A housing in the form of a hollow cylinder is attached to a motor base, a bearing is attached to the inner circumference side of the housing, and a motor substrate and a stator core are attached to the outer circumference side of the housing. A rotor including a magnet is rotatably attached via the bearing with a rotor shaft of the rotor inserted inside the housing.
The housing is produced by machining from a metal matrix or cutting a material that has been molded in advance by die-cast molding for example, and is fixed to the motor base by screws or the like. Alternatively, the housing may be drawn into a cylindrical shape and fixed using screws (see Patent Document 1).
Other examples of housings in use are a housing that is integrally formed from a metal base material by burring (see Patent Document 2) and a construction where a bearing housing is integrally molded when molding a motor casing from resin (see Patent Document 3). Other housings in use are produced by combining resin molding with metal components (by insert or outsert molding).